Switch member and method of producing the same



June 5, 3928. 1,672,123

H. A. HARTRANFT SWITCH MEMBER AND METHOD OF PRODUCING THE SAME FiledMarch 6, 1925 I fs? 1 INVENTOR.

2 1 Sax; 1% #1 d. I

151 ATTORNEY. 21a 11 21a Patented June 5, 1928.

' UNITED STATES PATENT OFFICE.

KENT MANUFACTURING COMPANY, OF PHILADELPHIA,

PORATION OF PENNSYLVANIA.

PENNSYLVANIA, A COB- SWITCH MEMBER AND METHOD 0]? PRODUCING THE SAME.

Application filed March My invention relates to switch members,

and more particularly to the movable or rotatable members of electricswitches, rheostats and the like.

In accordance with my invention, a switch blade or contact of anelectric switch, rheostat or the like, of conducting material, isprovided with two perforations, one of which is forced over and along astud, shaft or the like,thereby effecting frictional holding engagementtherewith, and the other perforation is forced over a lug or boss, ef-

fecting frictional engagement therewith, to

prevent the blade or contact member from movin or rotating with respectto the shaft or stu Further in accordance with my invention, the stud orshaft may be utilized for effecting electrical connection with the bladeor contact, and may be molded in a knob or operating member, with whichmay be integrally molded the lug or boss.

My invention resides in the structure and method .ofthe characterhereinafter described and claimed.

For an understanding-of my method, and for an illustration of one of thevarious forms my structure may take, reference is to be had to theaccompanying drawing, in which:

Fig. 1 is a vertical cross sectional view of a rheostat embodying myinvention.

Fig. 2 is a bottom plan view of the knob or cap with the parts carriedthereby.

Fig. 3 is a plan view of the switch blade or contact.

Fig. 4 is a plan view, on larger scale, of portion of Fig. 2.

Fig. 5 is a sectional view' taken on the line-5.5 of Fig. 4.-

- Referring to the drawing, 1 is a casing member integral with which ismolded the base 2 of a .phenol condensation product, condensite or thelike upon which may be mounted switch contacts, or, as indicated, the

resistance wire 3 of an adjustable resistance or rheostat disposed inany suitable form, as, for example, in the form of a helix, asindicated, lying in a channel between the flanges 4 and 5. v

The knob or cap 6 of insulating material has molded therein theroughened end 7 of the stud or stub shaft 8 of conducting mmterial andof substantially circular cross sec- 6, 1925. Serial No. 13,558.

'tion. Carried by the cap is the switch blade or contact member 9,preferably of sheet metal, as phosphor bronze, spring brass or the like,and bearing at its outer end 10 upon a switch contact or, in the exampleillus-.

trated, upon the resistance conductor 3. The member 9 has theperforation or hole 11, through which the shaft 8 extends, and the tailor extension 12. having the elongated hole or perforation 13 co-actingwith the boss or lug 14 molded integral with the member 6.

The shaft 8 extends loosely through the base 2 and is provided near itslower end with the circumferential groove 15, in which engages thebifurcated end 16 of a resilient conducting member 17 secured by thebinding post screw 18 and effectingv electrical connection between thebinding post 19 and the. shaft 8 and through it with the contact member9.

The initial or normal diameter of the hole 11 in the contact member 9 issomewhat smaller than the diameter of the stud or shaft 8. The member 9is placed upon the free end of the shaft 8 with the aperture 11 inregister with the shaft, and the member 9 is then forced downwardlyalong the shaft, causing the formation of a lip, flange or member 20,which frictionally holds the member 9 up'on the shaft 8 and effects ggodelectrical connection therewith.

The usual soldering of the member 9 to the stud 8 is dispensed with, forthe electrical contact effected by the flange 20 forced u on the member8 is good and of sufliciently ow resistance without soldering. Thesoldering usually employed has had the effect of preventing the contactmember from loosening and rotating upon the shaft. To prevent suchloosening and rotation of the contact member with respect to the shaft8, the ex- ,shaft 8, but must faithfully follow the rotary movements ofthe shaft 8 and knob 6.

The radial length of the aperture 13 is preferably greater than thediameter of the tapering or tapered boss or lug 14 when the member 12reaches the position shown in Figs. 1 and 5. The width of the aperture13 between its sides 21, 21 is slightly less than the diameter of theboss or lug 14 at its lower or free end, or in any event less than "itsdiameter at that portion. of its length occupied by the member-12 whenin .the position indicated in Figs. 1 and 5. The

member 12 is forced along the lug 14, cutting or shaving materialtherefrom at and by the sides 21 of the slot 13, in effect flatteningthe sides of the lug 14, as shown'in Figs. 2 and 4, reducing the widthof the lug 14 from its 14, thereby opposing loosening or'removal of theextension 12 toward ihe free end of the boss 14.

It will be understood that the; contact member 9 may be forced to theposition indicated in Figs. 1, 2, 4 and 5 by placing it upon the outeror free end of the shaft 8 in such position that the aperture 13 comeslater into register and engagement with the lug 14, whereby the finalportion of the movement of the member 9 along the shaft 8 issimultaneous with the movement of itsextension 12 over and along the lug14, suitable holding or press structure being pro vided for so applyingthe member 9 to the cap or knob. structure.

Accordingly, the member 9, without soldering .or equivalent, effectsgood eleC- trieal'connection with the shaft 8, is frictionally heldthereon by the lip or flange 20, and is prevented from rotating upon orwith respect to the sha ft 8 by the lug 14, which holds the member 9firmly in the desired position indicated in Figs. 1, 2, 4 and 5.

The radial elongation of" the aperture 13 serves to permit smallvariations in the distance between the lug 14 and the center of theshaft 8, as may readil occur in the usual molding operations; an furtherserves to localize the engagement of the edge of the aperture 13 withand upon the lug 14.

Upon the upper side of the base 2 may be molded integral therewith theboss or projection 23 disposed in the circular path of travel of the lug14, to serve as a sto to limit the extent of rotation of thehand e orcap 6.

In consequence, the lug 14 in the example illustrated and describedserves the dual pose of a limiting stop and also to hold and preventrotation of the contact member 9.

What I claim is:

1. In the art of producing contact mem-- bers, the method whichcomprises providing a lug 0T1 the support for the contact mem-' ber, andforcing the lug through an aperture n the contact member to removematerial of the lug and effect a biting engagement 3. In the art of.producing contact members, the method which comprises providing a lug onthe support for the contact member, and forcing the lug through anaperture in the contact member to remove material of the-lug andmaterially deform the wall of the aperture to effect biting engagementbe-' tween the contact member and'said lug.

4. In the art of producing contact members, the method which comprisesproviding a lug on the support for the contact member, and forcing thelug through an elongated aperture in the contact member to removematerial of the lug and materially deform the walls of the aperture atits narrow portion to effect biting engagement between said contactmember and said lug.

5. In the art "of producing contact meni-' bers, the method whichcomprises providing the support for the contact member with a stud. anda lug spaced from each other, and forcing said stud and lug throughapertures in the contact member to effect frictional holding engagementbetween said contact member and said stud and lug.

6. A contact member having a support, a stud and a lug carried therebyand spaced from each other, said contact member having apertures throughwhich said stud and lug extend and by which it is frictionally heldagainst movement with respect to said support.

7. A contact member having a support, a stud and. a lug carried therebyand spaced from each other, said contact member having apertures throughwhich said stud and lug extend and atwhich said contact memberhas,aflange and a lip engagin respectively, said'stud and said lug.

8. A contact member compnsinga support of insulating material, a studmol d therein,

a lug molded integral with said support, anda contact arm havingapertures through which said stud'and lug extend and at which saidcontact arm is frictionally held by said stud and lug.- r

9. A contact member comprising a support of insulating material, aconducting stud molded therein, a lug molded integral with said support,and a contact arm having an aperture through which said stud extends andat which said contact arm is frictionally held in current-conductingrelation with said stud, said contact arm having a second aperturethrough which said lug extends and at which the wall of said aperturehas biting engagement with said lug.

' 10. A contact member comprising a support of insulating material, aconducting stud molded therein gral with said having an aper extends andat a tapered lug molded intesupport, and a contact arm ture throughwhich said stud which said contact arm'is held'in current-conductingrelation with said stud, said contact arm having a second e1on gatedaperture through which said-lug extends and at which the opposite sidewalls at the narrow po rtion of said aperture have stud and lug,

a contact arm having apertures through 20 Y which said stud and lugextend and at which said contactvarm is frictionally held to said aconducting member on said base with which said contactarm co-acts, and amember on said base disposed in the 25 path of travel of said lug.

HARRY A. HARTRANFT.

